The Australian Institute of Marine Science’s 2025–26 monitoring report found different changes in hard coral cover across the Great Barrier Reef’s three surveyed regions. Published on August 11, 2026, the report covered 121 reefs surveyed between August 2025 and June 2026. It reported regional estimates, not a single average for the entire Reef. AIMS annual summary
Estimated hard coral cover in the Northern region rose from 30.0% to 35.1%. In the Central region it increased from 28.6% to 31.6%. The Southern region recorded a slight decline, from 26.9% to 26.4%. Presenting all three figures is necessary to describe the mixed regional picture.
AIMS’ long-term programme uses field surveys, including manta-tow observations, to assess reef conditions. Coral cover is one measure of condition; its regional variation means a statement about one region should not be generalized automatically to every reef or to the whole ecosystem.
The Great Barrier Reef Marine Park Authority’s summary reports the same regional changes and says cover remained close to long-term averages in the AIMS record. The published figures therefore support a regional comparison, rather than the earlier blanket characterization of a reef-wide record high. Marine Park Authority summary
Archive note: the earlier reef-wide 20-year-high characterization was not supported.